1. Field of the Invention
The invention relates to a multilayer ceramic substrate constructed of a combination of a plurality of ceramic materials having electric characteristics and/or physical characteristics that are different from each other and a its production method.
2. Description of the Related Art
A multilayer ceramic substrate is formed of a plurality of ceramic layers and conductive lines are formed along the interfaces between the respective ceramic layers. Usually, the multilayer ceramic substrate is manufactured by laminating green sheets of plural kinds of ceramic materials having electric characteristics and/or physical characteristics that are different from each other so as to achieve multiple functions and high performance and by firing the produced composite laminated body at the same time. This is because electronic elements required to have different dielectric characteristics such as capacitor and inductor are integrally formed in the multilayer ceramic substrate.
In order to produce such a multilayer ceramic substrate, the following means have been proposed in the related art.
(1) A method of laminating plural kinds of ceramic layers that contain ceramic materials providing different electric characteristics from each other, respectively. For example, a method of laminating plural kinds of ceramic layers that contain dielectric ceramic materials having different dielectric constants from each other, respectively, and ceramic layers that contain a magnetic ceramic material (for example, see Japanese Patent Application Laid-Open (JP-A) No. 2001-144438 (patent document 1)).
(2) A method of forming spaces in a not-yet-fired laminated body of green sheets, inserting not-yet-fired molded body blocks in the spaces, and then firing the molded body blocks and the laminated body of green sheets at the same time (for example, see JP-A No. 61-288498 (patent document 2), Japanese Patent No. 3322199 (patent document 3), JP-A No. 11-163530 (patent document 4), and JP-A No. 11-87918 (patent document 5)).